1. Field of the Invention
The present invention relates to flexible fixing materials for catheters and the like.
2. Discussion of the Background
For radiotherapy of tumors in body cavities, for example in the pharynx, intestine or vaginal regions and in body regions opened up by surgery, brachytherapy with catheters is a recognized method in which the radiation source or sources, controlled by an afterloading instrument, can be applied precisely to the treatment site in the body and can be moved such that a previously calculated course of the radiation dose over the treatment area results, as described by D. E. Wazer, R. Schmidt-Ullrich, W. Chasin, A. Wu, M. Buscher in Am. J. Otolaryngology 10 (3), (1989), 173, and by R. Stepan, P. Lukas, U. Fink, P. Knetschaurek, Ir. Siewert, M. Molls in "Intraoperative Radiotherapy with High Dose Afterloading (Flabs Method) in Colorectal Carcinom" (in F. W. Schildberg, N. Willich, H. -J. Kramling, "Intraoperative Radiation Therapy", Proceedings 4th International Symposium IORT, Munich 1992, Verlag Blaue Eule, Essen).
To avoid damage to patients and to ensure an exact irradiation plan, the catheters must be positioned accurately and fixed on or in the body. Only if this is ensured can the required course of isodoses be programmed and the planned irradiation be effected with the necessary safety and precision.
The usual practice for the production of fixed catheter sets is to cut rubber-like standard flat blocks (1 to 3 cm high, area: 30.times.30 cm; sources of supply are, for example, Quandt Medizintechnik, Hamburg, or Mick Radio Nuclear Instruments Inc. Bronx, N.Y.) to size and then to hollow a needle through them manually so that they can then be fitted with the catheters. This process has the disadvantage that because of the friction and adhesion between the outer wall of the needle and the flexible material, the rubber-like plastic body deforms and the parallel nature of the channels is lost.
Furthermore, these so-called flabs cannot be fixed reliably to the application site. Tears at the puncture site of the fixing thread and thus movement or even complete detachment of the flabs often occur.
Against this background, the invention of a flab fitted with catheters, in accordance with U.S. Pat. No. 4,963,128, was an advance, but this does not yet fully meet practical requirements.
Kneschaurek, Wehrmann, Hugo, Stepan Lukas and Molls in Strahlentherapie und onkologie 171 (1995), page 61, describe a cast silicone applicator which uses hollow plastic needles which are pushed parallel to one another into the central plane of the flab with the aid of a special device. However, the authors report difficulties in introduction of the needles, so that the cast silicone bodies must often be discarded.
Cylindrical plastic catheter systems likewise are not available. Plastic components bored through by the individual himself are therefore used as improvisation, as described in the publication cited above by D. E. Wazer et al., page 177.